During this first period, the lower fertilizer prices were farmers mainly in western Europe, the United States, Canada, response of farmers in these countries to the cheaper fertilize: large part of the increases in crop production. But throughout countries-except for Taiwan (51), Mexico (18), and a few cheaper fertilizer did not reach the mainstream of farmers in During the second period, which began in 1964-65 and is cont of producing nitrogen is declining substantially once again as of an additional major technical advance. Furthermore, the cc potash has also declined as the production of potash has Canada.* Now, belatedly, many more farmers in low incorr obtaining fertilizer at prices relative to the price of food g makes it profitable for them to use fertilizer, especially whe tilizer-responsive varieties of grains are at hand. But this proce from cheap fertilizer has only just begun; it will take more th these low income countries to exhaust the agricultural produc ties from this source.
Later, when 1 turn to the production of wheat and rice, I the stage is now set throughout major parts of the low incor produce food grains at lower real cost than formerly. The cheaper fertilizers, along with the high-yielding varieties of 1 has become a strong dynamic factor in this process. The folk in millions of metric tons (4) provide a perspective of the upw< total quantity of world consumption of fertilizer nutrients.'
The fertilizer tonnage doubled between 1955-56 and 1965' increase has been rising further since then. The less develope
*The more recent decline in the price of sulphur is now reducing tl ing phosphate fertilizers.
'A very rough measure of the additional crop production that is tec! approximately 5 tons of grain for each ton of fertilizer nutrients ap million additional tons of fertilizer used in 1967-68 compared to expressed in terms of additional wheat, implies an increase of 45 uiilli 1.66 billion bushels of additional wheat (52).t, from advances in industrial technical knowledge. Since the end of the 1930's there have been two series of price declines. The first occurred before 1964-65 and the other since then. The following data show that in the United States fertilizer prices declined by one half relative to farm products prices during the decade from 1939-40 to 1950. (If one were to use the consumer price index, the relative decline would be very much the same.)